Fluorine-18 fluorodeoxyglucose (FDG) positron emission tomography (PET) studies imaging FDG PET imaging is used to detect and stage head and neck cancers. However, the variable physiologic uptake of FDG in different normal structures as well as at inflammatory sites may either obscure a tumor focus or be falsely interpreted to represent tumor activity. Twenty-one patients (9 men, 12 women, median age 59) were scanned serially at two time points, one at 70 min (range 47-112) and the second at 98 min (77-142) after the intravenous injection of 4.3 MBq/kg of FDG. The mean interval between emission scans was 28 min (13-49). Transmission scans were performed and regions of interest (ROIs) were overlayed on the fully corrected images. Standardiued uptake values (SUVs) were generated for the cerebellum, tongue, larynx, every lesion, and a matched contralateral site. Follow-up and pathologic studies revealed 18 squamous cell carcinomas and nine inflammatory or infectious lesions. Tumor SUVs were 4.0+/-1.6 (mean +/- SD) for the first scan and 4. 5+/-2.2 for the second scan. Contralateral SUVs were 1.2+/-0.5 and 1. 1+/-0.5 for the two scans. Tumor SUVs increased by 12%+/-12% as compared with a 5%+/-17% decrease for contralateral sites (P<0.05). SUVs for inflammatory sites (2.0+/-0.7 and 2.0+/-0.9), cerebellum (4. 2+/-1.3 and 4.3+/-1.4), tongue (1.8+/-0.4 and 1.9+/-0.5) and larynx (1.5+/-0.6 and 1.5+/-0.6) remained constant over time (+0.6%, +2.8%, +1.4%, and -2.4%; P<0.05 when compared with tumor SUV changes). The ratio tumor/contralateral SUV increased by 23%+/-29% over time while this ratio for inflamed sites increased by only 5%+/-15% (P=0.07). The time interval between scans correlated with increase in SUV for tumors (r=0.55, P<0.05) but not for any of the other ROIs. Separation was superior when studies were performed more than 30 min apart (P<0.05). These preliminary data suggest that dual time point imaging compatible with a clinical study protocol is helpful in differentiating malignant lesions from inflammation and normal tissues, especially when separated by a sufficient time interval.

No abstract

No abstract

We present an updated, subjective list of the extant, non-marine ostracod genera and species of the world, with their distributions in the major zoogeographical regions, as well as a list of the genera in their present hierarchical taxonomic positions. The list includes all taxa described and taxonomic alterations made up to 1 July 2018. Taxonomic changes include 17 new combinations, 5 new names, 1 emended specific name and 11 new synonymies (1 tribe, 4 genera, 6 species). Taking into account the recognized synonymies, there are presently 2330 subjective species of non-marine ostracods in 270 genera. The most diverse family in non-marine habitats is the Cyprididae, comprising 43.2% of all species, followed by the Candonidae (29.0%), Entocytheridae (9.1%) and the Limnocytheridae (7.0%). An additional 13 families comprise the remaining 11.8% of described species. The Palaearctic zoogeographical region has the greatest number of described species (799), followed by the Afrotropical region with 453 species and the Nearctic region with 439 species. The Australasian and Neotropical regions each have 328 and 333 recorded species, respectively, while the Oriental region has 271. The vast majority of non-marine ostracods (89.8%) are endemic to one zoogeographical region, while only six species are found in six or more regions. We also present an additional list with ‘uncertain species’, which have neither been redescribed nor re-assessed since 1912, and which are excluded from the main list; a list of taxonomic changes presented in the present paper; a table with the number of species and % per family; and a table with numbers of new species described in the 20-year period between 1998 and 2017 per zoogeographical region. Two figures visualize the total number of species and endemic species per zoogeographical region, and the numbers of new species descriptions per decade for all families and the three largest families since 1770, respectively.

Left frontotemporal activation during episodic encoding and retrieval, which is associated with better recognition in healthy people, is disrupted in schizophrenia despite relatively intact recognition performance and right prefrontal function. This may reflect impaired strategic use of semantic information to organize encoding and facilitate retrieval.

No abstract

Three living male darwinulid ostracods of a new species of the genus Vestalenula have been found in Yakushima, Japan. This is the first report of living darwinulid males for over 100 years and their morphology casts doubt on the two previous records from the late 1800s. The presence of male darwinulids also calls into question the hypothesis that the family Darwinulidae is an exclusively ancient asexual group, reproducing without sex for over 200 million years (Myr). Male carapaces are of similar size and shape to A-1 juvenile females of the same species, suggesting that males may have been dismissed as A-1 juveniles in other living and fossil species. The antennae and fifth limbs are sexually dimorphic: the male antennae have six segments compared with five in the female and a series of putative chemical receptors originating at the extra segment boundary, while the male fifth limbs have well-developed grasping hooks, as in males of many ostracod groups. The lack of Zenker's Organ and of complex internal structures within the hemipenis contradicts previous hypotheses of the phylogenetic position of darwinulids.

Eight subjects with late-life depression, eight subjects with probable Alzheimer disease, and eight healthy age-matched controls were studied using 2-[18F]fluoro-2-deoxy-D-glucose positron emission tomography in the resting state with their eyes open and ears unoccduded. The depressed subjects showed widespread reductions in the regional cerebral metabolic rate for glucose in most major neocortical, subcortical, and paralimbic regions that were signiScantly different from control values (P < 0.01). The metabolic decrements in the depressed group were comparable in magnitude to those seen in the Alzheimer dLwase group. These data demonstrate widespread nonfocal decline in glucose metabolism in late-life depression that is comparable to the hypometabolism seen in Alzheimer disease. These findings have pathophysiological impLications in major depressive disorder in the elderly.Depressive illness is one of the most common mental disorders in the elderly (1, 2). It typically presents as a pervasive disturbance of mood associated with neurovegetative and cognitive signs and symptoms such as disturbance of sleep and appetite, crying spells, fatigue, anhedonia, and loss of attention, concentration, and memory (1, 2). The prevalence of major depressive illness-the most severe form of the disorder-is estimated to be -1% in studies of noninstitutionalized elderly subjects (3). The prevalence of dysthymic disorder and depressive symptoms-less severe but clinically significant forms ofdepression in the same population-is 2-3 and 10-15%, respectively (3). Depression in the elderly is often associated with functional and economic loss, physical illness, institutionalization, and a high rate of suicide (1,2). Despite these staggering consequences, late-life depression remains one of the most underdiagnosed and undertreated conditions in the elderly (1, 2).While the structural basis of late-life depression has been investigated using computerized tomography and magnetic resonance imaging (4-9), there have been very few studies aimed at elucidating the physiologic basis of late-life depression (10, 11). Cerebral blood flow has been examined using the xenon-133 inhalation technique and single photon emission computed tomography (SPECT) in a mixed sample of elderly and younger subjects with major depression and in a small group of subjects with late-life depression (10, 11). Global reduction in blood flow, in the major neocortical regions, has been reported to occur in these subjects when compared to healthy age-matched controls (10). However, given the technical limitations of the xenon-133 technique, only cortical blood flow was examined by this method (10). The question of subcortical, paralimbic, and cerebellar physiological activity in subjects with late-life depression remains unanswered (10). Semiquantitative estimates of blood flowThe publication costs of this article were defrayed in part by page charge payment. This article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. §1734 solely t...